So, he throws a small party for his family and friends at his home in Blackmoor Castle.

That same night, he's visited by a black-hooded stranger who accuses Lucius of possessing some recently-stolen diamonds.

He demands that the hot loot be returned, but Lucius scoffs. The masked man departs, vowing swift vengeance.

As proof of his violent intent, he leaves behind him the mangled body of Lucius' groundskeeper, strangled and branded with a mysterious 'M' on the dead man's forehead.

Who could this madman be? What does he really want? Lucius and his niece Claridge (Dor) have little time to piece together the clues.

Because, before long, more murders are being committed...and it seems like they're next on the killer's list!

This German suspense flick is one in a series of krimi ('crime thrillers') based on the mystery fiction of Edgar Wallace. (Other krimi include The Phantom of Soho in 1964, and The Blue Hand in 1967).

Unfortunately, Strangler of Blackmoor is too unfocused to be one of the stronger krimi.

The plot is serviceable, but the characters are blandly drawn, and the action sequences few and far between. Only Dor musters some charisma, and the scene where she's terrorized by an electric drill is the best moment here.

German: Der Würger von Schloß Blackmoor.